1. Field of the Invention
This invention relates to a heater core mounting structure, more particularly to a heater core mounting structure for mounting a stacked-plate heater core in a heater case when assembling a heater unit.
2. Background Art
A conventional heater core mounting structure will be briefly explained with reference to FIG. 6.
FIG. 6 is a side sectional view of a heater unit 1. The heater unit 1 has a heater case 2, a heater core 3 and linings 4 made of urethane resin or the like to serve as mounting members.
The heater core 3 has multiple stacked plates 5 whose main surfaces are formed by aluminum brazing or the like with ridges and valleys for forming passages. The plates 5 are stacked in the direction perpendicular to the drawing sheet to establish heat exchange medium passages between adjacent plates 5. A tank 6 is provided at one end of the stacked plates 5. Stacked end portions 5A of the stacked plates 5 project at positions on the opposite side from the tank 6.
The tank 6 is connected with an inlet pipe 7 and an outlet pipe 8 for the heat exchange medium.
The linings 4 serving as mounting members between the tank 6 and the heater case 2 and between the end portions 5A and the heater case 2 absorb vibration and provide thermal insulation. The linings 4 in combination constitute a mounting structure 9 for mounting the heater core 3 in the heater case 2.
Different heater units 1 may, however, be used in different environments and seasons that require installation of heater cores 3 of different thicknesses. In this case, one of multiple (e.g., two) types of heater cores 3 is selected for mounting in each heater case 2.
When a heater core 3 of a different thickness becomes necessary, a choice has had to be made among fabricating a new type of heater case 2, modifying the existing heater case 2, and fabricating the heater core 3 that should rightly be of different thickness to the same thickness T as the heater core 3 of greater thickness. All three alternatives lead to a great increase in cost.
One conceivable way to avoid this problem is by manufacturing the heater case 2 in conformity with the thicker heater core 3 and fitting the thinner heater core 3 with spacers (not shown) that enable it to be mounted as if it had the same thickness as the thicker heater core 3. This would minimize cost increase because it does not require modification of the heater case 2 or the shape of the thinner heater core 3.
It has so far not been a satisfactory solution, however, because the positioning of the spacers for mounting on the heater core 3 has been difficult. Specifically, a shift has tended to occur in the stacked direction of the plates 5 when the spacers are mounted on the heater core 3.
In the case of the heater core 3 of stacked structure, moreover, the end portions 5A of the stacked plates 5 are present as a large number of thin projections sticking out slightly from the main bodies of the stacked plates 5 and are therefore easily damaged during handling.
FIG. 7 shows a conventional arrangement in which a cooler unit (evaporator 10) and an air-mixing door 11 are disposed on the upstream side of a heater core 3, an associated bypass 12 is established and an air-mixing chamber 13 is formed on the downstream side so that warm and cold air can be mixed at an appropriate ratio in the air-mixing chamber 13.
With this arrangement, any change in the thickness of the heater core 3 changes the volume of the air-mixing chamber 13, which may in turn alter the air-mixing performance. An attempt to reestablish or maintain the air-mixing performance by design changes or adjustments inevitably requires alterations to the entire housing.
Heater core mounting structures are taught by, for example, Japanese Utility Model Disclosures Sho 51-55547, Sho 58-99107, Sho 59-133306 Sho 61-89668, Sho 61-122107 and Hei 2-96205.
This invention was accomplished in light of the foregoing problems and has as one of its objects to provide a heater core mounting structure enabling heater cores of different thickness to be mounted in the same heater case.
Another object of the invention is to provide a heater core mounting structure enabling heater cores of different thickness to be mounted in the same heater case with minimal cost increase.
Another object of the invention is to provide a heater core mounting structure capable of preventing shift of the stacked plates of the heater core when spacers are mounted on the heater core.
Another object of the invention is to provide a heater core mounting structure capable of protecting the end portions of the stacked plates when a stacked-plate heater core is mounted in a heater case.
Another object of the invention is to provide a heater core mounting structure that enables the volume of an air-mixing chamber to be maintained or varied independently of the thickness of the heater core, thereby facilitating the maintenance and/or adjustment of air-mixing performance.